The trend in the circuit protection industry is currently toward complete circuit protection which is accomplished by the addition of supplemental protection apparatus to standard overcurrent protective devices, such as molded case circuit breakers. U.S. Pat. No. 4,622,444 entitled "Circuit Breaker Housing and Attachment Box" describes an accessory that can be field-in-stalled within a circuit breaker without interfering with the integrity of the circuit breaker internal components. This is accomplished by mounting the accessories within a recess formed in the circuit breaker enclosure cover.
An electronic trip actuator which is mounted within the circuit breaker enclosure is described within U.S. Pat. No. 4,679,019 entitled "Trip Actuator for Molded Case Circuit Breakers". The circuit breaker actuator responds to trip signals generated by an electronic trip unit completely contained within a semi-conductor chip such as that described within U.S. Pat. No. 4,589,052. The development of a combined trip actuator for both overcurrent protection as well as accessory function is found within U.S. Pat. No. 4,700,161 entitled "Combined Trip Unit and Accessory Module for Electronic Trip Circuit Breakers". The aforementioned U.S. Patents which represent the advanced state of the art of circuit protection devices are incorporated herein for reference purposes.
A shunt trip accessory unit allows the circuit breaker operating mechanism to be articulated from a remote location to separate the circuit breaker contacts, usually to perform a tripping function for electrical system control and protection. One such shunt trip accessory unit is described within U.S. patent application Ser. No. 133,867 filed Dec. 16, 1987 entitled "Molded Case Circuit Breaker Shunt Trip Unit". An auxiliary switch accessory unit allows an operator to determine the "ON" or "OFF" conditions of a molded case circuit breaker contacts at a remote location by means of an audible alarm or visible display. One such auxiliary switch unit is described within U.S. patent application Ser. No. 133,868 filed Dec. 16, 1987 entitled "Molded Case Circuit Breaker Auxiliary Switch Unit". Both of the aforementioned U.S. Patent Applications are incorporated herein for purposes of reference.
A more recent example of a combined overcurrent trip actuator and multiple accessory unit is described within U.S. patent application Ser. No. 133,869 filed Dec. 16, 1987 entitled "Molded Case Circuit Breaker Multiple Accessory Unit" which combined overcurrent trip actuator and multiple accessory unit requires a separate mounting recess within the circuit breaker cover to house the printed wire board that carries the accessory control circuit. U.S. patent application Ser. No. 163,589 entitled "Molded Case Circuit Breaker Actuator-Accessory Unit" describes one such combined overcurrent trip actuator and multiple accessory unit wherein the printed wire board and actuator-accessory unit are both contained within the same mounting recess within the circuit breaker cover. U.S. patent application Ser. No. 176,589 describes an actuator-accessory module wherein the electromagnetic actuator and electronic control circuits are self-contained within a single unitary module. U.S. patent application Ser. No. 185,723 entitled "Molded Case Circuit Breaker Actuator-Accessory Module" describes an arrangement whereby a separate actuator-accessory module is selected for different combinations of accessory functions. All of the aforementioned U.S. Patent Applications are incorporated herein for reference purposes.